Double-tube return bend



C. H. TRUE.

DOUBLE TUBE RETURN BEND. APPLICATION FILED APR. I6, .320.

1.4.1 1,762. Patented Apr. 4, 1922.

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UNITED STATES.

PATENT orrl cs. I

CHARLES HENDERSON TRUE, OF HAMMOND, INDIANA, ASSIGNOR TO THE SUPER- Hum OOMIEANY, OF .NEW YORK, N. Y., CORPORATION OF DELAWARE,

DOUBLE-TUBE RETURN BEND.

Original application filed May 24, 1919,

To all whom it may concern v Be it known that I, CHARLES H. TRUE, a citizen of the United States, residing at Hammond, in the county of Lake and State of Indiana, have invented certain new anduseful Improvements in Double-Tube Return Bends, of which the following is 'a specification.

My invention concerns itself with pipe arrangements in which one set of pipe lies within another, the ends of each set of pipes being connected by return bends so that independent inner and outer conduits are formed. It has for its purpose the provision of an improved form of the return bends connecting the pipes and a novel mode of making them. The advantages of "a return bend according to the present invention and of the proposed method of making it will appear clearly This description is to be read in connection with the accompanying drawing. In the latter, Figs. 1 and 2 show portions of two of the outer and two of the. inner pipes connected, the one by an incomplete and the other by a substantially complete return bend; Fig. 3 illustrates the same two parts placed in the relative position which they are to occupy finally Fig. 4 is a section online 44 on Fig. 3; Fig. 5 shows the return bend "after an additional step has been taken to:

ward finishing it; Fig. 6 shows the completed double-pipe return bend; 7 is a longitudinal central section of Fig. 6 taken at rightangles toit; and Fig. 8 illustrates a modification.

The present case is a division of application, Serial No. 299,623, of May 24, 1919.

In making the constituent parts of my double-pipe return bend, I employ the method described fully in U. S. Patent 1,169,209 to myself and N. T. McKee as joint inventors. The incomplete return bend illustrated in Fig. 1 is made by the process described in that patent. The die employed in its manufactureis usually re ferred to as a breeches die on account of its shape and will be so referred to hereinafter. The return bend as shown in Fig. 1 will hereinafter be referred to as an incomplete return bend. By it, the two pipes 1 and 2 are joined, the material being portions if the pipes themselves. The struc- Specification of Letters Patent.

Patented Apr. 4, 1922.

Serial No. 299,623. Divided and this application filed April 16, 1920. Serial No. 374,304.

ture is at this stage open at the end 3. It is assumed herem that the reader is familiar with the patent mentioned, above and with this art in general and no a detailed descriptlon of the process of making this incompletebend is' believed necessary. The structure illustrated in Fig. consists of the two pipes 4 and 5 joine at their ends by a return bend 6, which, it will be noticed, is closed at its end 7 and has projecting from it a relatively long nub 8. This return bend, 6 is made by the same process as the one of Fig. 1 and is closed preferably by swaging machine as fully described in U. S. Patent 1,255,355 to myself and C. A. W. Brandt as joint inventors. The pipes 4 and 5 will be seen in Fig. 2 to have received a double bend or ofi'set at the points 9 and 10. This is for the purpose of placing the The two structures thus briefly described I are placed one inside of the'other as illustrated in Fig. 3. They are held in this relative position by any means desired. Thereafter the incomplete return bend of the outer structure is suitably heated and swaged down as at 11, in Fig. 5. By an additional step which is merely a continuation of the swaging just spoken of, this return bend is finally closed as shown in Fig. 6. It will be found to advantage in practice, during the step of drawing down the outer incomplete return bend to the shape of Fig. 5, to place the inner structure so that its crotch 12 will be in contact with the point 13 of the inner structure and to hold the two'in the relative position they are to occupy, only during the bendvis drawn down and connected to it as shown. This is of utility in certain'places.

It will be manifest that numerous variations, not only in the method employed in producin my double tube return bend, but also in t e return bend itself'will occur in practice.

What I claim is:

1. A device of the type described comprising in combination a pair ofpipes connected by a return bend inte ral with them, a pair of smaller pipes inside of the first pair connected by a return bend integral with them, and a connecting portion extending from the end of the inner return bend to the outer return bend and integral with both. r

prising in combination a pair of pipes connected by a return bend integral with them,

a pair of smaller pipes inside of the first pair connected by a return bend integral with them, and a hollow connecting portion extending from the end of the inner return bend through the outer return bend and integral with both.

3. A device of the type described comprising in combination a pair of pipes connected by a return bend integral with them, a pair of smaller pipes inside of the first pair connected by a return bend integral with them, and means integral with both return bends to make the interior of the inner return bend accessible.

CHARLES HENDERSON TRUE. 

